Accuracy of self-perception and Body Mass Index compared to actual body fat percentage in athletes and non-athletes.

BACKGROUND: The purpose of this study was to examine the accuracy of self-reported weight status compared to weight status based on actual body fat percentage in athletes and non-athletes. METHODS: Adult athletes (N.=76; 43 female and 33 male) and non-athletes (N.=80; 43 female and 37 male) participated in this cross-sectional study. Participants were asked to identify their perceived weight status. Height and weight were measured, and BMI was calculated. Body fat percentage was assessed using BOD POD. Cross-tabs analyses were used to determine agreement between perceived weight status, weight status based on body fat percentage, and weight status based on BMI. RESULTS: Overall, agreement between perceived weight status and actual weight status based on body fat percentage was fair. Of the 43 overweight/obese participants, 42% under-estimated weight status, thinking they were normal weight. Of the 114 normal weight participants, 6% over-estimated their weight status, thinking they were overweight. Although there were lower rates of overweight/obesity among athletes, 50% of overweight/obese athletes thought they were normal weight, while 39% of overweight/obese non-athletes thought they were normal weight. None of the normal weight athletes (N.=56) over-estimated their weight status. In contrast, 20% of male non-athletes, and 9% of female non-athletes who were normal weight thought they were overweight. CONCLUSIONS: Similar to trends observed in recent studies, results from the current study indicate that a high proportion of overweight/obese adults underestimate their weight status, and athletes may not be immune to this trend. Reasons as to why this phenomenon may be occurring and future directions are discussed.

LOCATION OF BODY FAT AMONG WOMEN WHO ACCURATELY OR INACCURATELY PERCEIVE THEIR WEIGHT STATUS.

This cross-sectional study investigated location of body fat, with specific focus on abdominal fat, among normal weight and overweight women who accurately or inaccurately perceived their weight status. Young, adult women (N = 120; M age = 19.5 yr., SD = 1.2) were asked to classify their weight status using the Self-Classified Weight subscale from the Multidimensional Body-Self Relations Questionnaire. Actual weight status was operationalized via dual-energy x-ray absorptiometry. Overweight women who thought they were normal weight had an average of 19 pounds more fat than normal weight women with 1.5 pounds of excess abdominal fat. Interventions to raise awareness among overweight women unaware of their fat level are warranted. However, these interventions should balance consideration of potential detriments to body image among these women.

The Efficacy of a Walking Intervention Using Social Media to Increase Physical Activity: A Randomized Trial.

BACKGROUND: Facebook may be a useful tool to provide a social support group to encourage increases in physical activity. This study examines the efficacy of a Facebook social support group to increase steps/day in young women. METHODS: Female college freshmen (N = 63) were randomized to one of two 8-week interventions: a Facebook Social Support Group (n = 32) or a Standard Walking Intervention (n = 31). Participants in both groups received weekly step goals and tracked steps/day with a pedometer. Women in the Facebook Social Support Group were also enrolled in a Facebook group and asked to post information about their steps/day and provide feedback to one another. RESULTS: Women in both intervention arms significantly increased steps/day pre- to postintervention (F(8,425) = 94.43, P < .001). However, women in the Facebook Social Support Group increased steps/day significantly more (F(1,138) = 11.34, P < .001) than women in the Standard Walking Intervention, going from 5295 to 12,472 steps/day. CONCLUSIONS: These results demonstrate the potential effectiveness of using Facebook to offer a social support group to increase physical activity in young women. Women in the Facebook Social Support Group increased walking by approximately 1.5 miles/day more than women in the Standard Walking Intervention which, if maintained, could have a profound impact on their future health.

Responsiveness of motion sensors to detect change in sedentary and physical activity behaviour.

BACKGROUND: The purpose of this study was to determine the responsiveness of two motion sensors to detect change in sedentary behaviour (SB) and physical activity (PA) during an occupational intervention to reduce sitting time. METHODS: SB and PA were assessed using a hip-worn Actigraph GTX3 (AG) and a thigh-worn activPAL (AP) during three consecutive workdays throughout baseline and intervention periods. Mean scores at baseline and intervention were estimated by hierarchical linear models (HLM) with robust SEs, adjusting for random variance of average scores between participants. Change scores (mean baseline minus mean intervention) were calculated for each device. Response to change was assessed for each device using the standardised response mean. RESULTS: 67 adults (45 ± 11 years; 29.3 ± 7.7 kg/m(2)) wore the acceleration-based motion sensors for 8.3 (SD=1.2) and 8.3 (SD=1.1) h during the baseline and intervention periods, respectively. HLM showed that AP sitting/lying time (-16.5 min, -5%), AP stepping (+7.5 min, 19%), AP steps/day (+838 steps/day, +22%), AP sit-to-stand transitions (+3, +10%), AG SB (-14.6 min, -4%), AG lifestyle moderate-intensity PA (LMPA, +4 min, +15%) and AG MPA (+3 min, 23%) changed significantly between the baseline and the intervention period. Standardised response means for AP sitting/lying time, stepping, steps/day, sit-to-stand transitions and AG SB, LMPA and MPA were above 0.3, indicating a small but similar responsiveness to change. CONCLUSIONS: Responsiveness to change in SB and PA was similar and comparable for the AP and AG, indicating agreement across both measurement devices.

Prompts to disrupt sitting time and increase physical activity at work, 2011-2012.

INTRODUCTION: The objective of this study was to assess change in sitting and physical activity behavior in response to a workplace intervention to disrupt prolonged sitting time. METHODS: Sixty office workers were randomized to either a Stand group (n = 29), which received hourly prompts (computer-based and wrist-worn) to stand up, or a Step group (n = 31), which received the same hourly prompts and an additional prompt to walk 100 steps or more upon standing. An ActivPAL monitor was used to assess sitting and physical activity behavior on the same 3 consecutive workdays during baseline and intervention periods. Mixed-effect models with random intercepts and random slopes for time were performed to assess change between groups and across time. RESULTS: Both groups significantly reduced duration of average sitting bouts (Stand group, by 16%; Step group, by 19%) and the number of sitting bouts of 60 minutes or more (Step group, by 36%; Stand group, by 54%). The Stand group significantly reduced total sitting time (by 6.6%), duration of the longest sitting bout (by 29%), and number of sitting bouts of 30 minutes or more (by 13%) and increased the number of sit-to-stand transitions (by 15%) and standing time (by 23%). Stepping time significantly increased in the Stand (by 14%) and Step (by 29%) groups, but only the Step group significantly increased (by 35%) the number of steps per workday. Differences in changes from baseline to intervention between groups were not significant for any outcome. CONCLUSION: Interventions that focus on disrupting sitting time only in the workplace may result in less sitting. When sitting time disruptions are paired with a physical activity prompt, people may be more likely to increase their workday physical activity, but the effect on sitting time may be attenuated.

Associations between lifestyle physical activity and body image attitudes among women.

Structured exercise can improve body image among women. Less is known if these associations extend to lifestyle physical activity-all activities of daily living with a full range of intensity. The purpose of this cross-sectional study was to examine the relationships between lifestyle physical activity and body image in undergraduate women (n = 120; 18-23 years) during the spring of 2010 and 2011. One week of lifestyle physical activity was measured objectively (accelerometer) and subjectively (7-Day Physical Activity Recall Questionnaire). Attitudinal dimensions of body image were assessed using the Multidimensional Body-Self Relations Questionnaire. Physical activity was unrelated to appearance-related dimensions of women's body image. Objectively-measured vigorous physical activity was positively related to investment in fitness and health (p < .005), while moderate physical activity was related to investment in fitness (p < .005). Light physical activity was unrelated to women's body image. A greater amount of self-reported vigorous physical activity was related to greater investment in fitness (p < .005). Results suggested that unlike structured exercise, lifestyle physical activity was generally unrelated to women's body image. The act of exercising may be more important than accumulation of lifestyle physical activity when considering women's body image.

Prediction of body fat in older adults by time spent in sedentary behavior.

The purpose of the study was to determine the relationship between sedentary behavior (SB), physical activity (PA), and body fat (total, abdominal) or body size (body-mass index [BMI], waist circumference [WC]) in community-dwelling adults 50 yr old and over. This study included 232 ambulatory adults (50-87 yr, 37.4% ± 9.6% body fat [BF]). Average daily time spent in SB (<100 counts/min) and light (100-759 counts/min), lifestyle-moderate (760-1,951 counts/min), walking-moderate (1,952-5,724 cts/min), and vigorous-intensity (≥ 5,725 counts/min) PA were determined by accelerometer and corrected for wear time. BF was measured with dual-energy X-ray absorptiometry. SB was positively related to measures of BF. Measures of SB, PA, and gender accounted for 55.6% of the variance in total BF, 32.4% of the variance in abdominal fat, and 28.0% of the variance in WC. SB, PA, and age accounted for 27.1% of the variance in BMI. Time spent in SB should be considered when designing obesity interventions for adults 50 yr old and over.